The present invention relates to a new benzothiadiazine compound.
1. Field of the Invention
It is now acknowledged that excitatory amino acids, and most particularly glutamate, play a crucial role in the physiological processes of neuronal plasticity and in the mechanisms underlying learning and memory. Recently, pathophysiological studies have indicated clearly that a deficit in glutamatergic neurotransmission is closely associated with the development of Alzheimer's disease (Neuroscience and Biobehavioral reviews, 1992, 16, 13-24; Progress in Neurobiology, 1992, 39, 517-545).
Moreover, numerous works have illustrated in recent years the existence of receptor subtypes for excitatory amino acids and of their functional interactions (Molecular Neuropharmacology, 1992, 2, 15-31 ).
Among these receptors, the AMPA receptor ("a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid") appears to be the one most involved in physiological neuronal excitability phenonema and especially in those involved in the processes of memorization. For example, learning has been shown to be associated with the increase in the binding of AMPA to its receptor in the hippocampus, one of the regions of the brain essential for mnemocognitive processes. Similarly, nootropic agents such as aniracetam have been described very recently as positively modulating the AMPA receptors of neuronal cells (Journal of Neurochemistry, 1992, 58, 1199-1204).
2. Description of the Prior Art
Very recently, compounds of benzamide structure have been described as possessing the same mechanism of action and as improving memory performance (Synapse, 1993, 15, 326-329). The compound BA 74, in particular, is the most active among these novel pharmacological agents.